Available nutrients status in black soils of Varanasi district of eastern part of Uttar Pradesh

Soil fertility status of the intensively vegetables growing in black soils of Varanasi (UP), India is not available. Therefore, present study was under-taken to assess the fertility status by collecting 100 surface (0-15 cm depth) soil samples using geographical positioning system (GPS). Soil samples were analysed following standard methods. The pH of the surface soils ranged from 7.3 to 8.4 with a mean of 7.9 indicating alkaline nature of soil. The EC of the soils were normal and ranged from 0.17 to 0.48 dS m-1 with mean value of 0.30 dS m-1. The organic carbon content of the soils ranged from 3 to 9 g kg-1 with a mean of 5.8 g kg-1. The range (mean) values of available N, P and K were 106 to 291 (184), 8 to 65 (27) and 145 to 358 (229) kg ha-1, respectively. The soils were found 99% low in available N content and nutrient index rating of available P was found high. The range (mean) values of B, Zn, Cu, Fe and Mn were, 0.11 to 0.53 (0.40), 0.38 to 3.04 (1.08), 0.22 to 1.96 (0.79), 2.9 to 16.40 (8.42) and 0.68 to 12.64 (3.24) mg kg-1 soil, respectively. The available sulphur of the soils ranged from 7 to 33 mg S kg-1 with mean of 15 mg S kg-1 soil. Soils were categorised in to low, medium and high status, subsequently 99 % soils were found low in available nitrogen whereas 63% soil samples were found medium in available phosphorus, and 88% were medium in available potash. 26, 48 and 26% soils were low, medium and high in S, respectively and the corresponding Figs. for B were 90, 10 and 0%. In case of cationic micronutrients, 7, 58 and 35% soils were low, medium and high in Zn and the corresponding Figs. for Available Mn were 30, 44 and 26%. Fe was found 6, 59 and 35% in low, medium and high category respectively. There was no copper deficiency found in black soils of Varanasi.